Process of purifying and desulfurizing crude petroleum and petroleum distillates.



5 cause complete oxidation.

50 ating the oil.

UNITED STATES.

"PATENT.- OFFICE.

THEODORE F. COLIN, on ELIZABETH, NEW JERSEY, AND OTTO P. AMEND, on NEWYORK, N. Y.

PROCESS OF PURIFYING AND DESULFURIZING CRUDE PETROLEUM AN D' PETROLEUMDISTILLATES.

SPECIFICATION forming part of Letters Patent No. 723,368, dated March24, 1903. Application filed February 15, 1902. Serial No. 94,326. (MSpecimens-l To all whom it may concern.-

Be it known thatwe, THEODORE F. COLIN, residing in the city ofElizabeth, county of Union, and State of New Jersey, and OTTO P.

5 AMEND, residingin the city, county, and State of New York, citizens ofthe United States, have jointly invented a certain new and usefulProcess of Purifying and Desulfurizing Crude Petroleum and PetroleumDistillates,

' of which the following is a specification.

The object of our invention is to remove the sulfur from crude petroleumand its distillates by the use of active agents which are more efiectivewhen employed as described and to do it more cheaply than has heretoforebeen achieved by other processes.

We have observed that thesulfur contained in crude petroleum can bereadily removed by washing with an alkali or with sulfuric .0 acid afterit has been oxidized and that the extent of its removal depends upon thecompleteness of its oxidation.

Our invention is based upon the discovery that the oxidation'of thesulfur contained in crude petroleum or its distillates ismore use of anoxygen-carrier or catalytic agent,

and good results are obtained if the process.

be practiced at ordinary or slightly-elevated temperatures. We havediscovered that oxidizing action here is more important thanprecipitation and that those agents which,

like sodium plumbate, precipitate the less-refractory sulfur from thehydrocarbon compounds, but have too weak an oxidizing action on them,are insufficient for our purpose.

Thus although sodium plumbate has been used as an oxidizing agent andgives a pre cipitate of the sulfur in the form of an insoluble sulfid ithas only-a weak oxidizing action, and the object of our invention is toWe therefore use strong oxidizing agents which do not causeprecipitation. We have found that chlorin is the most satisfactoryoxidizing agent; but the sulfur must be removed without chlorin- Ofcourse chlorin produces a hypochlorite in an alkaline solution, and

without other oxidizing agents for purifying Oils which are not intendedfor high-grade illuminating-oils; but such solutions of thehypochlorites will in their use liberate some free chlorin, which entersinto'combination, with the hydrocarbons of the oil, especially those ofan unsaturated character, such as the olefines, and the chlorin is notreadily removed thereafter. The presence of chlorin, however, in a goodilluminating-oil is detrimental, especially if much more chlorin wereput in than sulfur taken out.

In order to insure the production of oxygen alone without'free chlorin,we employ as a catalytic agent which acts as an oxygen-carrierpreferably a salt of a metal which forms two or more oxids, which byoxidation or reduction, respectively, easily pass from one stateofoxidation to a higher or lower state. Suitable salts for this purposeof producing a very pure oxygen from, the hypochlorite solution are thenitrates of manganese, cobalt, nickel, copper, and iron. It is necessaryalso besides this catalytic agent to have the solution distinctlyalkaline in order to prevent the formation of free chlorin, and thoughthis can be assured by the addition of a caustic alkali to the solutionit is generally unnecessary to make such addition, as the solution ofthe hypochlorites of the alkaline metals or alkaline earthy metalspractically always contain an excess of alkali, and if our preferredprocess be practiced the oil will be alkaline through its previoustreatment with soda. The third important condition is the introductionof the chlorin in such a way that there shall be at no time any excessof chlorin presentt'. e., the hypochlorite solution must be allowed torun into the oil very slowly and gradually (during the whole timenecessary for agitation) and only as fast as the catalytic agent canreact upon it. In orderto insure this result, we preferably first treatthe Oil, before subjecting it to the subsequent steps of our process,with a strong solution of canstic soda, the solution having a specificgravtion of sodium or calcium hypochlorite,

(bleaching-powder,) to which has been added a very small quantity ofmanganous nitrate, as hereinafter described. This manganous salt byinteraction with the alkali and hypochlorite present is converted intomanganese dioxid, which gives'up its oxygen to the sulfur compounds ofthe hydrocarbons, itself being reduced and then again reoxidized by thehypochlorite, and so on. The direct addition of manganese dioxid (MnO tothe oil a mixture might'be used; but it will not be as effective,because the manganese dioxid,-When introduced into the mixture, asdescribed,will exist in a much finer state of subdivison, as powderedmanganese dioxid is not as finely divided as the precipitate produced inthe solution by neutralization and agitation. The agitation is done bymeans of compressed air. This helps the oxidation and also carries awayany free chlorin that may be present; but under these conditions noappearance of any free chlorin can be detected either by the sense ofsmell or by visible fumes with ammonia. The reaction above describedtakes place more easily at a somewhat elevated temperature, andtherefore in cold weather the oil ought to be warmed. A temperature ofabout 40 centigrade is favorable; but satisfactory results are obtainedat a temperature of about 15 to 20 centigrade. When the nitro-prussidtest shows that all the 'sulfur has been oxidized, we stop theagitation, let 1 the fiuid settle, and draw off the lower alkalineliquid. Nitro-prussid of sodium gives a red color with sulfids inalkaline solution; but when on application of a drop of an aqueoussolution of nitro-prussid of sodium to a drop of petroleum previouslymade alkaline.

with a drop of sodium ethylate dissolved in alcohol there is noappearance of any red color. It indicates that the oxidation of thesulfur in the petroleum has been completed.

The quantity of the hypochlorite to be used depends upon the amount ofoxidizable sulfur present in the oil. We have found that if the oilcontains, for instance, 0.3 per cent. of sulfur, it requires about 0.2per cent. of chlorin for its oxidation, and if the amount of sulfur inthe oil and the amount of available chlorin in the hypochlorite solutionare known the proper quantity of the hypochlorite can be easilydetermined; but it maybe pointed out that a slight excess of thehypochlorite will cause no harm, (it will even save time,) for theexcess of the chlorin will l I be subsequently neutralized, as describedbe low.

Some hypochlorous acid (or its salt) will remain suspended or dissolvedin the oil, and this must be removed or destroyed. We effect this bytreating the oil with a reducing agent, which in contact with thehypochlorous acid or its salt will abstract the oxygen from it. Toaccomplish this double purpose of forming an indifierent or inactivechlorid and of freeing the distillate of the chlorin, we add to thestill slightly alkaline oil a solution of a salt of a metal which hastwo or morestates of oxidation, each of which easily passes into theother, so that it can act as a reducing agent. Suitable salts for thispurpose are ferrous sulfate, (copperas,) manganous sulfate, ferrous andmaganous nitrates, ferrous and maganous chlorids, ferrous and maga nousacetates, or sodium plumbate. As fer' cheap, We prefer to use this salt.A solution of copperas (or some one of the other salts mentioned above)added to the oil containing chlorin and agitated with itfor a littletime will interact with the chlorin, so as to form ferric chlorid, whichis harmless in the mixture.

With the hypochlorous acid present the reaction can be represented thus:

This equation also shows the necessity of a certain definite minimumquantity of the iron salt to bind or neutralize all the chlorin present.Of course manganous nitrate could be used at this stage also, asit hasbeen used in the previous one; but as the iron salts are cheaper weprefer to use them, since a muchlarger quantity of the agent is requiredhere.

If the methods above described have been followed carefully, the oil ordistillate isnow rendered free from refractory compounds. The totalsulfur has been reduced to about one-half the original quantity, andwhat remains is in a form which submits to the usual acid treatment ofpetroleum distillates. A little doctor t'. e.-,sodium-plumbate solutionwill show that all hypochlorous acid has been decomposed. As long asany of this latter is present sodium plumbate will turn black from theformation of lead peroxid. After letting the oil stand for a littlewhile to settle, drawing off the aqueous liquid, and washing thedistillate a couple of times with water, the oil is now ready for theusual treatment with sulfuric acid, alkali, and wannnecessary todescribe.

We may give the following as a specific exstood as illustrative only andnot exclusive. We took two hundred and fifty cubic centimeters of amixed petroleum distillate which conrous sulfate (copperas) is veryefiective and ter in the Well-known manner, which it is ICC ample of ourprocess, and it is to be undertained, in about equal volumes, thesaturated hydrocarbons which produce the water-white kerosene ofcommerce and the unsaturated hydrocarbons (mainly olefines) produced bythe cracking process of distillation, which gives only an inferiorburning-oil. The weight of the oil was about two hundred grams.

First. We washed this distillate with about five cubic centimeters of astrongsolution of caustic soda in order to neutralize acids, phenols,850., and separated the resulting alkaline sludge.

Second. We next added to the oil gradually, drop by drop, fifty cubiccentimeters of a solution of sodium hypochlorite. This solution wasstrongly alkaline (and therefore needed no addition of caustic soda) andcontained 0.48 grams of available chlorin in one hundred cubiccentimeters of the solution, or a total of 0.24 grams chlorin to twohundred grams oil 0.12 per cent. chlorin. To this we added one drop of aweak solution of manganous nitrate, as a catalytic agent, and agitatedthe liquid by means of an air-blast for one hour while the hypochloritewas dropping in. At the end of that time the sodium nitroprussid testshowed the absence of sulfids in the hydrocarbons; The temperature ofthe room was about 17 centigrade.

Third. After allowing the liquid to settle and drawing off the alkalinesolution we washed the oil four times with water- Fourth. Assuming as avery improbable maxim that one-eighth part of the chlorin previouslyadded still remained in the oil, we now added twenty cubic centimetersof a copperas solution containing 0.2 grams of solid ferrous sulfate andagitated the liquid with an air-blast for twenty minutes. At the end ofthat time a test of a small portion of the solution with sodium plumbateshowed that the plumbate did not turn black by the formation of PbO thusproving the absence of hypochlorous acid. We allowed the liquid.

' washing with Water and alkali.

The result was an oil of good color, standing the usual test with sodiumplumbate, free from manganese and iron, and containing (as shown by thecombustion test) a mere trace of chlorin and sulfur in quantitysufilciently low for commercial purposes.

The process described above may be practiced, as stated, by the use ofthe difierent agents described and will answer for the reduction ofsulfur in crude oils and their distillates.

Having thus described our invention, what we claim is l. The process ofdesulfurizing petroleum and its distillates which consists in theoxidation of the sulfur contained therein (without precipitation of thesulfur) by means of a hypochlorite in alkaline solution in the presenceof an oxygen-carrier or catalytic agent, at ordinary orslightly-elevated temperatures, substantially as described.

2. The process of desulfurizing petroleum and its distillates whichconsists in theoxidation of the sulfur contained therein by means of ahypochlorite in alkaline solution at ordinary or slightly-elevatedtemperatures in the presence of an oxygen-carrier or catalytic agent,and the subsequent removal of the excess of chlorin by means of aferrous salts, substantially'as described.

3. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation ofthe sulfur contained therein by means of ahypochlorite in alkaline solution at ordinary or slightly-elevatedtemperatures, and the subsequent removal of the excess of chloin bymeans of a solution of a metallic salt having two or more states ofoxidation readliy transformable one into the other, sbustantially asdescribed.

4:. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation of the sulfur contained therein by means of ahypochlorite in alkaline solution in the presence of an oxygencarrier orcatalytic agent, at ordinary or slightly-elevated temperatures, and thesubsequent removal of the excess of chlorin by means of a solution of ametallic salt having two or more states of oxidation readilytransformable one into the other, substantially as described.

5. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation of the sulfur contained therein by means of ahypochlorite in alkaline solution in the presence of an oxygen-carrieror catalytic agent, at ordinary or slightly-elevated temperatures, andthe subsequent removal of the excess of chlorin by agitating with asolution of ferrous sulfate, substantially as described.

6. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation of the sulfur contained therein by means of ahypochlorite in alkaline solution in the presence of manganous nitrate,at ordinary or slightly-elevated temperatures, substantially asdescribed.

7. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation of the sulfur contained therein by means of anoxidizing agent in alkaline solution in the presence of manganousnitrate, at ordinary or slightly-elevated temperatures, and thesubsequent removal of the excess of chlorin by means of a solution of ametallic salt having two or more states of oxidation readilytransferable one into the other, substantially as described.

8. The process of desulfurizing petroleum and its distillates whichconsists in the oxidation of the sulfur contained therein by means of ahypochlorite in alkaline solution in thepresence of manganous nitrate,atordinary or slightly-elevated temperatures, and the subsequent removalof the excess of chlorin by IIS ' 723,368 4 A tsiutheoxidand itsdlstillates which consls means of ferrous sulfate, substantlally as deaim} of the sulfur contamedfligremigtggagi IS scribed. of desulfurizingpetroleum I ofan oxidizing," fientellgvadltlzaiipeergpemmrks, I n 3 il sislt i ll i e s which consists in the oxidaordgxzgiysggszligentylemovalof the excess of b means an bstan- 5 non of d' i dfr ;g:: 2:1 :31 a ll lil ie golution chlorin by meagsgf ferrous sulfate, su

9f l h e r 'er ange o f an oxygen-carrier or catatially as descri e IHEODORE F. COLIN. lg rtic agent, at ordinary or slighsly-eleggteg OTTOP. AMEND.

0 t eratures and the subsequen rem 1o thg xccss of hhlorin b3 mealpsdofferrous sul b tantially as escri e l%. "l h: process of desulfurizingpetroleum Witnesses:

W. HARRES, J AOOB B. TooH.

I It is hereby certified that in Letters Patent N 0. 723,368, grantedMarch 24:, 1903, upon the application of Theodore F. Colin, ofElizabeth, Nev; Jersey, and Otto P. Amend, of New York, N. Y., for animprovement in Processes of Purifying and Desulfurizing Crude Petroleumand Petroleum Distillates, errors appear in the printed specificationrequiring correction, as follows: On page 1, line 56, the word effectshould read aflect: page 2, line 52, a comma should be substituted forthe period after the Word color, and the following word It shouldcommence with a small 1 instead of a capital; same page, lines 84, 85and 85-86, the word maganous should read manganous; page 3, line 35, theword maxim should read maximum; same page, line 78, the Word saltsshould read salt; and in lines 87 and 88 the Words readily and Signedand sealed this 14th day of April, A. 1)., 1903.

[SEAL] F. I. ALLEN,

, Commissioner of Patents.

Corrections in Letters Patent No. 723,368.

